A WDM (Wavelength Division Multiplexing, wavelength division multiplexing) technology is a mainstream technology in the current optical transmission field, and can transmit optical waves of multiple different wavelengths in a single fiber synchronously. The wavelength path performs transmission on the network in an all-optical state, and intermediate nodes cannot obtain, like an SDH (Synchronous Digital Hierarchy, synchronous digital hierarchy) network, path information by extracting path overheads. Therefore, the wavelength path cannot be managed and maintained by using the path overheads.
In this case, a wavelength tracking technology emerges in the industry, that is, in each wavelength path, a low frequency signal is modulated by using a certain modulation scheme; after multiple wavelength paths are multiplexed, signals are transmitted through the main optical path. The frequency value of the low frequency signal and a binary code representing the modulation scheme form the wavelength identifier of the wavelength path. A node in the wavelength path splits a part of light from the main optical path, obtains, through demodulation, multiple low frequency signals added to multiple wavelength paths, determines, according to the wavelength identifier, a low frequency signal modulated in the wavelength path, and monitors the low frequency signal to obtain the transmission track and performance of a corresponding wavelength path. In this way, the management and maintenance of the wavelength path are implemented.
Currently, in this method, the performance of the wavelength path can be monitored only when a wavelength identifier is allocated to each wavelength path manually by using a network management system and a mapping relationship between the wavelength identifier and the wavelength path is configured into each node manfully by using the network management system. Therefore, the implementation is complex, and the reliability is low.